Agriculturally active ingredients, such as pesticides and plant growth regulators are conventionally distributed by spraying. There is however a problem for agrochemical spray droplets, mostly consisting of water, to deposit onto waxy plant leaf surfaces. One plausible reason for this is that the kinetic energy that the droplets have been given due to atomization when sprayed, is transformed into surface energy upon impact with the leaf surface. The droplet stretches out on the surface, but this high surface tension is not favourable, which means that the droplet is pulled back. This pullback is so energetic that part of the droplet, or even the complete droplet, detaches from the leaf surface. According to literature, as much as 90% of the solution sprayed onto the leaf could be lost by this phenomenon. There are two known ways to solve this problem, namely by adding a surfactant that can quickly go to the surface and lower the surface tension, or by adding a polymer to control the cohesion of the droplet. However, using a surfactant gives rise to another problem, namely the problem of drift. Both the problem with pullback and that with drift will reduce bio efficacy, since the agriculturally ingredient(s) will not reach the plant. By using polymers the problem with drift can be avoided. There are a number of different publications relating to polymers in pesticidal compositions for different purposes.
WO 98/56825 relates to a hydrophobically modified anionic cellulose ether used in anti-settling, associative thickening, and in foam, emulsion, and suspension stabilizations, in a number of different industries, e.g. in a time-released application including pesticides.
U.S. Pat. No. 6,534,563 B1 relates to the use of compounds with particular elongational and flow viscosity as an anti-rebound agent included in aqueous plant protection formulations. The compounds used are selected from hydrosoluble or hydrodispersible surfactant polymers with a molecular weight in the range 5×105 to 5×106 g/mol, including polysaccharide derivatives, such as cellulose and its carboxyalkylated or hydroxyalkylated derivatives, wherein the alkyl portion contains 1 to 4 carbon atoms.
WO 92/09197 relates to a herbicidal preparation comprising a polymeric stabiliser selected from a group of polymers all of which have a molecular weight of at least 7,000 Dalton, including hydrophobically modified non-ionic cellulose ethers.
However, there is still a need in the art for compositions comprising agriculturally active ingredients, which compositions have improved deposition properties.